Complex-shaped, finely-featured ZrC/W composites via shape-preserving reactive melt infiltration of porous WC structures fabricated by 3D ink extrusion

Additive Manufacturing Letters 2021 Volume 1, Article 100018

Complex-shaped, finely-featured, ultra-high-melting ZrC/W composite structures were produced by coupling, for the first time, three-dimensional (3D) ink-extrusion printing with shape/size-preserving reactive melt infiltration (the Displacive Compensation of Porosity, DCP, process). Inks containing sub-micron WC powders were printed at ambient temperature into either fine-scale structures (sub-millimeter filaments) or into a larger-scale, finely-featured 3D structure (a centimeter-scale nozzle with a sub-millimeter-thick wall). After organic binder removal, the printed structures were sintered at 1650 °C for 1 h to achieve a porosity of 50%. The porous, rigid WC structures then underwent ambient pressure infiltration and reaction with Zr-Cu liquid at up to 1350 °C for 2 h. The reaction of WC to yield more voluminous ZrC and W products filled prior pores (DCP process) to yield shape-preserved, dense ZrC/W structures after Cu dissolution from external surfaces. This new integrated approach opens the door to ultra-high-melting ceramic/metal composite structures with complex 3D shapes and fine (millimeter-scale) features.